As per the Carlo book, Casso tortured and extracted a confession from Jimmy Hydell, complete with all of the others involved. Casso left Hydell in his barely alive state and made him repeat the story to some top members of the Gambino family. Gotti refused to come, however, the confession was confirmed by the Gambinos.

With that in mind, Gotti and Ruggiero were very close and John wouldn't have whacked him, imo. And I believe that Gotti ordered Quack Quack to clip Casso- I don't really believe the bad drug deal story. The time frame can't be ignored as it was months after Casso arranged for Frank DeCicco to be bombed.

As far as Dwalin's question goes....Casso would have had Ruggiero whacked- because this is what he did with the others involved. Gotti would have gone insane, and this would have led to a mini war between the Lucchese/Genoveses vs Gambinos. I believe the Bonannos would have stayed out of this because they wanted to earn their seat back on the commission and going to war alongside the Gambinos would have killed their chances.